Android 2.2 added a JIT (Just-In-Time) compiler to the Dalvik VM. Dalvik is the interpreter that is the heart of Android and runs all your apps. (It is being superseded by ART in latest Android releases)

I was digging around in my build.prop looking for more stuff to do to my PE to try and get as much performance as I could out of the poor old thing when I noticed the Dalvik execution mode line. I did some googling and read up on Dalvik some and decided to try changing it to the JIT instead of the default failsafe "fast" mode. My Linpack results went from 3.1-3.2 MFLOPS average to 5.1-5.2MFLOPS which is a pretty drastic
increase.

The other thing I changed in my build.prop was the Dalvik heap size.I doubled the default heap size to 256MB from 128MB that is the default. The Dalvik heap size adjusts how much memory a Dalvik VM instance can use. The more memory a single app can use, the less often Dalvik has to run through its garbage collection routines. This takes a load off the CPU and may be one reason my PE has seemed so much snappier. This may just be placebo, though. It shouldn't cause any harm and the PE has 512MB of RAM to play with so... worth doing, imo.

Code:

dalvik.vm.heapsize=256M
dalvik.vm.execution-mode=init:jit

I have had my PE running with a 256MB heap for 2 years with no issues and a few days with the JIT on and no problems. I made the same changes to my friends PE today and he hasn't had any problems, either.

Android 2.2 added a JIT (Just-In-Time) compiler to the Dalvik VM. Dalvik is the interpreter that is the heart of Android and runs all your apps. (It is being superseded by ART in latest Android releases)

I was digging around in my build.prop looking for more stuff to do to my PE to try and get as much performance as I could out of the poor old thing when I noticed the Dalvik execution mode line. I did some googling and read up on Dalvik some and decided to try changing it to the JIT instead of the default failsafe "fast" mode. My Linpack results went from 3.1-3.2 MFLOPS average to 5.1-5.2MFLOPS which is a pretty drastic
increase.

The other thing I changed in my build.prop was the Dalvik heap size.I doubled the default heap size to 256MB from 128MB that is the default. The Dalvik heap size adjusts how much memory a Dalvik VM instance can use. The more memory a single app can use, the less often Dalvik has to run through its garbage collection routines. This takes a load off the CPU and may be one reason my PE has seemed so much snappier. This may just be placebo, though. It shouldn't cause any harm and the PE has 512MB of RAM to play with so... worth doing, imo.

Code:

dalvik.vm.heapsize=256M
dalvik.vm.execution-mode=init:jit

I have had my PE running with a 256MB heap for 2 years with no issues and a few days with the JIT on and no problems. I made the same changes to my friends PE today and he hasn't had any problems, either.

It might be helpful if those of you who put up articles about changing files like build.prop, go through the steps of how to change build.prop for those fellow travelers who would like to benefit from these improvements but are a little bit nervous about how to actually implement them without turning their beloved PEs into the dreaded "brick"

Android 2.2 added a JIT (Just-In-Time) compiler to the Dalvik VM. Dalvik is the interpreter that is the heart of Android and runs all your apps. (It is being superseded by ART in latest Android releases)

I was digging around in my build.prop looking for more stuff to do to my PE to try and get as much performance as I could out of the poor old thing when I noticed the Dalvik execution mode line. I did some googling and read up on Dalvik some and decided to try changing it to the JIT instead of the default failsafe "fast" mode. My Linpack results went from 3.1-3.2 MFLOPS average to 5.1-5.2MFLOPS which is a pretty drastic
increase.

The other thing I changed in my build.prop was the Dalvik heap size.I doubled the default heap size to 256MB from 128MB that is the default. The Dalvik heap size adjusts how much memory a Dalvik VM instance can use. The more memory a single app can use, the less often Dalvik has to run through its garbage collection routines. This takes a load off the CPU and may be one reason my PE has seemed so much snappier. This may just be placebo, though. It shouldn't cause any harm and the PE has 512MB of RAM to play with so... worth doing, imo.

Code:

dalvik.vm.heapsize=256M
dalvik.vm.execution-mode=init:jit

I have had my PE running with a 256MB heap for 2 years with no issues and a few days with the JIT on and no problems. I made the same changes to my friends PE today and he hasn't had any problems, either.

I'm a noob, so I have no idea how to do this. Can you or anyone else explain how this is done?Thank you.

Hi, mjc. I will try and post an easy to follow step-by-step soon. I've been busy and failed to check on the forum. Sorry for the really delayed response. If you are still interested in doing this you can send me a private message and I can try helping quicker, as well.